Shakeel Ahmad Khandy

Structural, elastic and thermo-electronic properties of paramagnetic perovskite PbTaO3

Self-consistent ab initio calculations with highly precise spin-polarised, density functional theory (DFT) have been performed for the first time, to study the structural stability, mechanical and magneto-electronic properties of cubic perovskite PbTaO3. The DFT as well as the analytically calculated values of tolerance factor, in addition to stable-phase optimization, mechanical and elastic properties show stability of the present material in the cubic phase with a reasonably stiff nature and ductile properties. The symmetric spin-polarised band structure of both the spin (up and down) channels reveals zero spin polarisation at the Fermi level. Moreover, the insignificant total and individual spin magnetic moments of adjacent atoms and magnetic susceptibility calculations via the post-DFT treatment predict the paramagnetic nature of the material. Based on results of the present study, the paramagnetic metal PbTaO3 material is considered a promising candidate in designing new electrode materials.

Investigation of the transport, structural and mechanical properties of half-metallic REMnO3 (RE = Ce and Pr) ferromagnets

Systematic investigation of the ground state structure, which includes elastic and transport properties, of perovskite oxides REMnO3 (RE = Ce and Pr) has been carried out by first principles calculations. We present the analytical as well as DFT calculated equilibrium lattice constants which show good agreement with experimental data. Three independent elastic constants are emphasised to yield the corresponding mechanical properties, including the elastic moduli (B, G and Y), Poissons ratio (ν), anisotropy factor (A) and Pugh ratio B/G, for these compounds. These calculations predict the brittle PrMnO3 as a less hard material than the ductile CeMnO3 oxide. Post DFT treatment involving Boltzmanns theory is conveniently employed to investigate the thermoelectric properties of these compounds. The analysis of the thermal transport properties specifies the dimensionless figure of merit of 0.24 and 0.19 at room temperature for PrMnO3 and CeMnO3, respectively. Their half-metallic nature with efficient thermoelectric parameters, including electrical conductivity, Seebeck coefficient and thermal conductivity, suggest the likelihood of these materials to have a potential application in the design of shape memory devices and imminent thermoelectric materials.

Evaluation of mechanical and transport properties of Zr2CoSi Heusler alloy

Systematic investigation of mechanical and transport properties of Zr2CoSi within the density functional theory have been analysed. From the elastic constants, the shear modulus, Young’s modulus, Poisson’s ratio, we conclude the ductile nature of alloy. Thermoelectric properties show that Zr2CoSi as an n-type thermoelectric material with a higher increase in Seebeck coefficient with temperature. Further the power factor analysis confirms the heavily doping of the alloy fruitful for increase in thermoelectric performance and its use for the future thermoelectric spin generators.

Synthesis and structural characterization of transition metal doped MgO: Mg0.95Mn0.01TM0.04O (TM = Co, Ni, Cu)

In the present work, preparation and characterization of transition metal doped MgO: Zn0.94Mn0.01TM0.05O (TM = Co, Ni and Cu) nano-particles have been reported. Transition metal doped samples of MgO were synthesized by Sol gel auto combustion method. Structural characterisation from XRD and SEM show the formation of single-phase primary particles, nearly of spherical shaped nano-crystallites. The crystallite size was found to be 78.2, 67.02, 78.11 and 64 nm for pure, Co, Cu and Ni doped MgMnO nano-particles, respectively. Hence, the average crystallite size increases monotonously from Co to Cu doping.In the present work, preparation and characterization of transition metal doped MgO: Zn0.94Mn0.01TM0.05O (TM = Co, Ni and Cu) nano-particles have been reported. Transition metal doped samples of MgO were synthesized by Sol gel auto combustion method. Structural characterisation from XRD and SEM show the formation of single-phase primary particles, nearly of spherical shaped nano-crystallites. The crystallite size was found to be 78.2, 67.02, 78.11 and 64 nm for pure, Co, Cu and Ni doped MgMnO nano-particles, respectively. Hence, the average crystallite size increases monotonously from Co to Cu doping.

Correction to: Electronic Structure, Optical and Transport Properties of Double Perovskite La2NbMnO6: A Theoretical Understanding from DFT Calculations

Authors Khursheed Ahmad Parrey and Shakeel Ahmad Khandy included the names of Asad Niazi, Anver Aziz, and S. G. Ansari as co-authors of this article without their permission.

Structural and electronic properties of half-metallic rare-earth perovskites

Systemic investigation of structural parameters and electronic properties inclusive of band profiles for BaPaO3 and BaUO3 have been performed. The empirical as well as DFT calculated lattice constants are in agreement with the previously reported results. The critical energy values confirm that the BaPaO3 has lesser migration energy than BaUO3. Both, these materials show a semiconducting, direct band gap in the low spin state with 2.3 eV for BaUO3 and for BaPaO3, its value is 3.9 eV.

Transport properties of spin polarised quaternary CoMnVAs alloy

The electronic structure and transport properties of CoMnVAs quaternary Heusler compound has been investigated first time by using the density functional theory. The material was found half-metallic ferromagnet in F-43m structure. Positive values of the different elastic parameters also confirm its structural stability. Present study predicts an energy band gap of 0.55 eV in localized minority spin channel at an equilibrium lattice constant of 5.75A. Post-DFT treatment predicts this material to be an n-type thermoelectric along with a high Seebeck coefficient of -45μV K-1 at room temperature.